Esteban Santiago is taken from the Broward County main jail as he is transported to the federal courthouse in Fort Lauderdale, Florida, U.S., January 9, 2017. Amy Beth Bennett/South Florida Sun Sentinel via REUTERS

In 2016, the year that Esteban Santiago's life unraveled, he crossed paths with authorities in Anchorage again and again.

In each of his known interactions with Alaska's court and mental health system, the 26-year-old was treated as a troubled but run-of-the-mill customer — a man who got in fights with his girlfriend that hadn't yet translated to a criminal record, a psychiatric hospital patient who came in saying strange things but was deemed well enough to be released four days later, a citizen whose record and behavior did not disqualify him from having a gun.

But on Jan. 6 when he was seen opening fire at a Fort Lauderdale airport, Santiago stopped being simply a young man in crisis and became a mass-murder suspect.

Now, people in Alaska and beyond are trying to figure out how he slipped through the system, and whether it could — or should — have stopped him.

A year with a rocky start

Santiago began 2016 living in a small house on Medfra Street with his girlfriend, 40-year-old Gina Peterson. At the time, he was working for Signal 88 Security in Anchorage, a small franchise of a large security company based in Nebraska.

Peterson had for years been part of the small community of Bird Creek, down the Seward Highway from Anchorage, running the Birdhouse Garage with her then-husband and keeping animals like sheep and miniature horses on a 3-acre property, according to public records and Anchorage Daily News stories from the time. After a divorce, she moved to Anchorage and met Santiago.

Their relationship was troubled: On Jan. 10, 2016, Peterson told police Santiago had bashed down the bathroom door in their small Fairview home, smacked her on the side of the head and tried to strangle her, though a police officer investigating noted no injuries, according to a criminal complaint in the case.

Santiago was charged with misdemeanor domestic violence assault and criminal mischief and spent the week in jail before being released on bail Jan. 17, according to court records.

One of the conditions of his release was that he not see the victim. But on Feb. 16, he was picked up by police for violating his bail conditions when police found him at Peterson's home. Court documents said he admitted he'd been with her since he had been released from custody.

At a joint press conference with the FBI on Saturday, Anchorage Police Department Chief Chris Tolley described a series of encounters between police and Santiago during 2016 that had not led to an arrest. Three of them involved a report of violence of some kind.

On March 18, police went to a "physical disturbance" call involving Santiago, but there was not enough evidence to arrest him, Tolley said. Tolley didn't say whether this allegation involved Peterson or someone else and there's no independent court record.

A week later, on March 24, Santiago, who had no prior criminal history in Alaska, entered into a deferred sentencing agreement with municipal prosecutors on his January assault and criminal mischief charges, according to court documents. He agreed that if he completed a 12-week anger management class, paid a fine, made court appearances and didn't commit any "acts of violence" for a year, the charges against him would be dismissed March 28, 2017.

Such agreements are sometimes used as a way to get first-time offenders to straighten out their lives without ending up with a criminal record, though in Santiago's case, he did not complete the anger management course, according to municipal prosecutor Seneca Theno.

The deferred sentencing agreement left the case hanging in a legal no-man's land: Technically, Santiago was found to have committed a domestic violence offense, but Theno said the charge amounted to instilling fear in his girlfriend, not physically attacking her. By federal law, a misdemeanor domestic violence conviction involving fear but not hurt doesn't disqualify a person from having a gun.

Meanwhile, Santiago continued to work as a security guard for Signal 88. Co-worker James Foster, hired by Signal 88 in May, remembers him there.

Foster, who only worked at Signal 88 for four months, said he never knew his co-worker well, but Santiago did make an impression. Santiago, who drove his 1990s Ford Explorer to work, seemed to take pride in what he did. Foster described him as polite, professional and always on time.

They shared the same duties: Patrolling properties around Anchorage by car on the overnight shift, from midnight to 8 a.m., to check for people trespassing or otherwise making trouble.

Discharged from the National Guard, with a baby on the way

There is no court record of trouble in those spring and summer months.

But in August, he was discharged from the Alaska Army National Guard for "unsatisfactory performance." Details of what led to the discharge have not been released. The Associated Press reported that Santiago had "gone AWOL" several times in the past. The Guard said he was assigned to a unit based at Fort Wainwright in Fairbanks, but worked at the National Guard Armory in Anchorage. He never worked at the Guard's most sensitive operation, at the U.S. missile defense site in Fort Greely, said spokeswoman Lt. Col. Candis Olmstead.

In October, there were more encounters with police, but no charges. On Oct. 15, police were called to a domestic violence complaint involving Santiago, according to Tolley, the APD chief.

The call could have led to Santiago immediately losing his opportunity to keep the January assault and criminal mischief charges off his record. By Alaska law, if police find probable cause that a domestic violence assault has happened, they must arrest someone at the scene. The law is intended to address Alaska's high rate of domestic violence.

But on that day, officers investigating the domestic violence call consulted with prosecutors and got what Tolley described "authorization not to arrest Santiago."

Why did they ask for special permission not to arrest Santiago?

Municipal prosecutor Theno said she could not speak specifically to the facts of the incident. But generally speaking, there may simply not have been enough evidence to make an arrest, she said.

"We have to be able to prove the defendant committed the act," said Theno. "It is not enough that violence occurred."

Just a few days later, on Oct. 21, police again were called to a report of a strangulation involving Santiago, according to Tolley. Again, they found no probable cause to arrest him.

A building crisis

Then came Nov. 7, when Santiago walked into the FBI office to ask for help, bringing his baby with him. He told federal agents his "mind was being controlled by a U.S. intelligence agency." He was having "terroristic thoughts," officials said at a press conference.

The facts of what happened next are not clear because mental health records are kept confidential by law. But the FBI said that a police officer drove Santiago to a mental health facility. He only stayed a few days.

So what happened to Santiago after he got out of the psychiatric hospital?

But the Department of Public Safety didn't answer a question about whether Santiago even had a security guard license. And officials have also not said whether Santiago had any other hospitalizations.

Police have said that on Nov. 17 they sent a letter to Santiago about his gun, which was still being stored in the evidence area at police headquarters.

An appointment for pick up was made. If he was out of the hospital and not the subject of an involuntary commitment order, he would have been legally free to have it on mental health grounds. Only people who are involuntarily committed lose their firearm rights under federal law — and Alaska law is silent on the issue.

But on Nov. 30, when Santiago went to pick up the gun at APD headquarters, police for some reason called the FBI to meet him there.

They have not explained why. But Santiago did not take his gun home that day. But about a week later, on Dec. 8, Anchorage police returned the gun to Santiago.

Breaking into pieces

At the dawn of 2017, the shell of Santiago's already cracked life broke into pieces. In his last days in Anchorage he was renting a $30 per night "Japanese sleeping pod" at a hostel in Midtown, some of the Qupqugiaq Inn's residents told the Fort Lauderdale Sun-Sentinel. People in the neighborhood saw him getting pizza from a nearby shop. He was described by residents there as a paranoid loner.

But he was still relatively free: He had not a single criminal conviction on his record in Alaska. He had his gun. He could leave the state. He bought a plane ticket to New York, then cancelled it. Instead he chose a one-way ticket from Anchorage to Fort Lauderdale.

On Jan. 5, Santiago arrived at Ted Stevens International Airport for his flight four hours early, with no luggage. His only baggage he declared as he left his life in Alaska was a case with a handgun in it.